Page 84 - Gas Adsorption Equilibria

70 Chapter 1

dielectric and calorimetric measurements. However, as already mentioned,
experiments are cumbersome and time consuming and probably only will be
needed for calibration or standardization purposes or for processes operating
at high pressures.

In principle it also should be possible to determine absolute masses
adsorbed by analogously combined magneto-calorimetric or by magneto-
dielectric measurements, the later being probably the most favorable in view
of the highly sensitive experimental equipment available today. It also would
be desirable to compare results of measurements of absolute masses adsorbed
with those of numerical simulation models to get new insight for both the
analytical model used and the experimental technique proposed here [1.54].

6. LIST OF SYMBOLS

A list of most symbols (SI-units) and abbreviations used in this Chapter is
given.

surface area of a porous solid
determined by BET-measurements,
Sect. 4.3
De 1 Deborah number
d = 2r pore diameter
J integral heat or enthalpy of desorption

J/g specific enthalpy of desorption
g/mol molar mass of nitrogen
g mass of a monolayer adsorbate
g absolute or total mass of an adsorbed
phase or adsorbate, cp. Fig. 1 .20

g total mass of helium gas in an
adsorption system
g mass of sorptive gas phase which is
outside of the adsorbed phase
g Gibbs surface excess mass of a sorbate
phase, cp. Fig. 1.20